As TexMex says, I was told this can be caused by insufficient humidity. You can mist water over the plant daily and put a container of water near your heating so it evaporates. Other than that, I cut them off!
Remember these plants like to be in the cool shade, never in full or half sun. In Victorian and Edwardian times these were kept in a dark (ish) parlour with thick curtains and so rarely saw any full sun.
My old Granmother had a beautiful specimen that she kept in her dark cool front room and it thrived for years. She NEVER repotted it and only fed it once a week from the spring to autumn with cold tea and about once every three months she bathed the leaves with cotton wool dipped in milk.
I have a much smaller specimin that I treat in the same way and it's doing very well.